ANTIBIOTIC RESISTANCE IN MENINGOCOCCI 361
is not restricted to the penicillins in Australia. These
additional confounding factors make it difficult to assess the
impact of antibiotic resistance on the outcome and sequelae
of IMD under present circumstances. Additionally, most
cases of IMD in Australia are sporadic in nature and are
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caused by diverse serogroup B and C phenotypes.
There have been suggestions overseas that infections with
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with those with serogroup B organisms.
The data
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Australia.23 However, when strains from the same sample
were examined here, there was no difference in the
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cocci. This suggests that the differences in survival in IMD
caused by the two serogroups would be due to factors other
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Any in vitro resistance to the other antibiotics commonly
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infrequent and sporadic. All isolates were fully susceptible
to ceftriaxone and by extension to other third-generation
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The importance of continuing surveillance to establish
not only the proportion of strains with altered susceptibility
at any one time but also trends in antibiotic susceptibility
was reinforced in this study. This is best achieved using
continuing surveillance by reproducible and standard tech-
niques. The MIC data reported here were derived from
laboratories participating in a long-term monitoring pro-
gramme using established methods, and comparability of
data was further verified by a quality assurance programme.
Numeric MIC values derived by different testing procedures
are not usually comparable as use of different test methods
1
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2,25
may produce substantial variations in MIC values.
While the above findings suggest that antibiotic resist-
ance in N. meningitidis is not yet a major problem in
Australia, it would seem prudent to continue to monitor the
antibiotic susceptibility of meningococci. It is known that
meningococci have the capacity to acquire resistance by
mechanisms already elucidated in Neisseria gonorrhoeae,
albeit much less rapidly. The lessons learned from the
emergence and spread of gonococcal resistance can be
applied, in part at least, to meningococci given the high
degree of DNA homology between the two organisms. Such
data are important not only for individual patient manage-
ment with therapeutic antibiotics but also for public health
aspects of IMD control by means of chemoprophylaxis.
17. National Neisseria Network. The National Neisseria Network
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8. Australian Gonococcal Surveillance Programme. Penicillin sensitivity
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Comparison of broth microdilution and E-test for susceptibility testing
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A
CKNOWLEDGEMENTS The Commonwealth Department of
23. Australian Meningococcal Surveillance Programme. Annual report of
the Australian Meningococcal Surveillance Programme, 1999. Com-
mun Dis Intell 2000; 24: 181–9.
Health and Aged Care provided financial assistance to the
National Neisseria Network. Dr C. J. McIver performed the
statistical analyses.
24. Maiden MCJ, Spratt BG. Meningococcal conjugate vaccines: new
opportunities and new challenges. Lancet 1999; 354: 615–6.
2
5. Woods CR, Smith AL, Wasilauskas BL, Campas J, Givner LB.
Invasive disease caused by Neisseria meningitidis relatively resistant
to penicillin in North Carolina. J Infect Dis 1994; 170: 543–6.
Address for correspondence: Dr J. W. Tapsall, Department of Micro-
biology, The Prince of Wales Hospital, Randwick, NSW 2031, Australia.